Identification of novel tan spot resistance loci beyond the known host-selective toxin insensitivity genes in wheat

• Published in: Theoretical and applied genetics Vol. 117; no. 6; pp. 873 - 881
• Main Authors: Chu, C.-G, Friesen, T. L, Xu, S. S, Faris, J. D
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.10.2008; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Agriculture; Ascomycota - classification; Ascomycota - isolation & purification; Ascomycota - pathogenicity; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Breeding; Chromosome Mapping; Chromosomes; Classical genetics, quantitative genetics, hybrids; Drug Resistance - genetics; Fundamental and applied biological sciences. Psychology; Genes; Genes, Plant; Genetics of eukaryotes. Biological and molecular evolution; Host-Pathogen Interactions - genetics; Life Sciences; Mycotoxins - toxicity; Original Paper; Plant Biochemistry; Plant Breeding/Biotechnology; Plant Diseases - genetics; Plant Diseases - microbiology; Plant Genetics and Genomics; Polyploidy; Pteridophyta, spermatophyta; Quantitative Trait Loci; Triticum - drug effects; Triticum - genetics; Triticum - microbiology; Vegetals; Virulence; United States > US; North Dakota; North America; Doubled Haploid Population; Synthetic Hexaploid Wheat Line; Quantitative Trait Locus; Doubled Haploid; Quantitative Trait Locus Analysis; Resistance; Toxin; Monocotyledones; Gene; Gramineae; Angiospermae; Genetics; Spermatophyta; Agriculture; Identification; Locus; Triticum aestivum
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-008-0826-z

Tan spot, caused by Pyrenophora tritici-repentis, is a destructive foliar disease of wheat causing significant yield reduction in major wheat growing areas throughout the world. The objective of this study was to identify quantitative trait loci (QTL) conferring resistance to tan spot in the synthetic hexaploid wheat (SHW) line TA4152-60. A doubled haploid (DH) mapping population derived from TA4152-60 x ND495 was inoculated with conidia produced by isolates of each of four virulent races of P. tritici-repentis found in North America. QTL analysis revealed a total of five genomic regions significantly associated with tan spot resistance, all of which were contributed by the SHW line. Among them, two novel QTLs located on chromosome arms 2AS and 5BL conferred resistance to all isolates tested. Another novel QTL on chromosome arm 5AL conferred resistance to isolates of races 1, 2 and 5, and a QTL specific to a race 3 isolate was detected on chromosome arm 4AL. None of these QTLs corresponded to known host selective toxin (HST) insensitivity loci, but a second QTL on chromosome arm 5BL conferred resistance to the Ptr ToxA producing isolates of races 1 and 2 and corresponded to the Tsn1 (Ptr ToxA sensitivity) locus. This indicates that the wheat-P. tritici-repentis pathosystem is much more complex than previously thought and that selecting for toxin insensitivity alone will not necessarily lead to tan spot resistance. The markers associated with the QTLs identified in this work will be useful for deploying the SHW line as a tan spot resistance source in wheat breeding.